Bradley Perrett | We need to think about what we'd do if the US gave up resisting China

But we'd better think about what we'll do if a future Republican presidential administration decides it has had enough of underwriting the security of allies on the other side of the Pacific.

Such a change could come suddenly. Then China would move to assert authority over East Asia, Australia and New Zealand.

Until 2016, we might have thought the possibility of the US abandoning us and our region was insignificant. But that's been impossible to assume since Donald Trump won the presidential election in November that year with promises always to put America first.

A month later he suggested, in his foggy way, that getting a trade deal with China could affect how the US dealt with Taiwan. Did he mean "If the Chinese buy more of our soybeans, maybe they can have the island"?

We'll never know whether China could have clinched withdrawal of US support from Taiwan, because President Xi Jinping was far too aggressive to try giving Trump enough concessions. The two countries ended up in a trade war and rising acrimony.

Now Republicans, quite as much as Democrats, are settled on regarding China as the US's main antagonist. Good.

But Trumpian Republicans have turned half isolationist. They care little about containing rampaging Russia.

The main difference is that China is clearly an American problem - it has taken US jobs and ruthlessly stolen US technology - whereas Russia seizing territory in Europe can be dismissed as a European problem.

That's not entirely nuts. Russia has an economy that's about as big as Australia's, well under half the size of Germany's and less than a tenth of the combined GDP of the US's European allies - most of which have bludged for decades on the American taxpayer, spending too little on their own defence.

MORE AGE OF THE DRAGON:

Of course Americans should do what they can to stop Russia acting like Nazi Germany. They should indeed do more than they're doing now. But they're perfectly justified in resenting having to do anything at all when Europeans alone could be giving Ukraine everything it needs to resist Vladimir Putin.

I bet the statement "Europeans should handle Europe's problems" would get clear majority support among American voters and nearly 100 per cent backing from Trumpians.

How about the statement "Asians should handle Asia's problems"? Let's hope no one conducts that poll.

Someone has already conducted a more general poll asking Americans whether their country should pay less attention to foreign troubles and instead look after its own problems. More than two-thirds of Republicans thought it should.

It's now hard to see how a future Republican president can be an internationalist, in the style we became used to after Dwight Eisenhower took office in 1953. So, there'll be no more Nixons, Reagans and Bushes, Republican presidents who immersed themselves in international affairs and were willing to throw US weight into resisting far-away aggressors.

So, despite current anger with China, the risk of US withdrawal from the Western Pacific will rise every time a Republican moves into the White House. It may be elevated even during a Democratic presidential term if the administration senses that enough voters are fed up with spending money and US lives in sorting out the world's problems.

Notice that Barack Obama, overlearning the lessons of the second Iraq war, was far more cautious internationally than his Democratic predecessors Kennedy, Johnson, Carter and Clinton. The average American did not complain.

We don't yet seem to be near the point of US withdrawal from the Western Pacific, thanks to China getting Americans so annoyed. Especially under Xi Jinping, China is more and more like the kaiser's Germany in its antagonism of other countries. When it does wrong and provokes a reaction, its blustering, nationalist response is to push even harder.

If Trump wins the presidency again next year, popular sentiment against China should keep him focused on resisting it. Still, he's so unpredictable, and now so angry with establishment politics, that we can't rule out him being persuaded to go soft on China by some deft move by Beijing, perhaps on trade.

Also, he or a successor could simply shrink from the horrible possibility of war with China, which would hold great advantages in fighting on its own side of the Pacific to take Taiwan.

How would Trump or a later isolationist president react to the military advice that might be offered if China looked ready for war? "We can probably stop them," the admirals and generals might say. "But we could fail. And, either way, you have to count on losing at least 10,000 American lives."

US withdrawal to its own side of the Pacific would leave Australia, New Zealand, Japan and maybe South Korea struggling desperately to preserve themselves from Chinese overlordship. Other countries in China's region would see no hope. They'd just cave in.

This is a scenario we must consider. I'd like to think that we have extensive secret plans for it, but the policy performance of our defence establishment gives no reason to believe it is capable of thinking so far out of its comfort zone.

Any such planning would demand lifting defence spending as soon as possible to lay long-term groundwork for what may have to become a greatly expanded military.

There's no sign of that. Anthony Albanese and Jim Chalmers have refused to provide any immediate increase in the defence budget.